Relay for use in controlling atmospheric conditions



OCL 2, 1951 A. J. HILGERT 2,569,762

RELAY FOR usE IN CONIROLLING ATMOSPHERIC CONDITIONS n Filed May 1, 1947 v Snventor Adalph J .Hilg er1:

E MQ..

Gttornegs Patented Oct. 2, 1951 UNITED STATES `iih'fbl'f 0 FFICE` 2,569,762 RELAY FoRUsE 1N C ONTROLLI'NG ATMOSPHERIC CONDITIONS `Adolph J.- 'lI-ilgert, Milwaukee, Wis., assigner to Johnston ServicaCompany, Milwaukee,- Wis., a corporation of Wisconsin pplicatioliMayl, 1947, SerialNo. 745,342

2 Claims. 1`

The'invention relates to pneumatic relays, and particularly to that type commonly controlled by leak ports, and .used for controlling temperature, humidity and thelike.n

The invention provides a novel positive acting class 2 relay; i, e.- one in which .rise and `fall of pilot pressure past a critical value causes respectively, a sudden exhaust `and a sudden .full development of the controlled :I Jressiire.w

AA preferred-embodiment of the invention will now be described `by reference to Atheaccompanying drawing, in which:

Fig. 1 is an axial section of the relayI arranged as a class-two positiveaction-instrumenti Fig. 2 is `a View `indicating the parts in Fig. 1 which `give the instrument `its operative characteristics;

Figure l is diagrammatic tothe extent `that the supply passage, branch passage andleak port passage are drawn ras if they lay in a single plane (the plane of section) whereas-incommercial embodiments other arrangements of these ports are commonly more convenient. The leak port and the lid are showm- `but no ractuating mechanismfor the lid is shown, since it may take yany of a wide varietyofknown commercial forms,

and is not a feature of the invention.

The `body 6 of the instrument has `a mounting flange 1. Aline 8 supplies `air at uniform-.pressure (say 1.5 p. s. i.) to passage 9 which `is in free `communica-tion with `supply chamber `I I.

Suppl-y chamber II is separated Afrom the branch line space I2 by .the inletvalve-assembly which comprises the 4seat .bushingv I34 inlet valve ball- I4, thrust member I5 and biasing-spring I6.

Spring I6 seatsi-n plug 'I-l, which closes the back of chamber I I.- The val-ve seat isr-thefshoulderl and the spring AI 6 biases the valve 1in theopening direction.

`Closing theY front of chamber I2-is thereardi- `aphragm 2I which is clamped `by ring `22,'vvith inward extending nan-ge 2,3. The n'angezaiimi-ts outward displacement of diaphragm .12h VSupported by ring 22 and clamped Vby the cup-"like cover 24 is the rontdiaphragm 2,5. The cover, the ring and the diaphragm; are clamped by screws 26, which `are threaded `into body 6*.

The space 2'! between thediaphragms 2t and 275 is Vented to atmosphere byport 218. The space 29 between Yfront diaphragm 25` and cover-24 is the space in which the pilot pressure isy developed; Air under pressure .is fed from 4po''t 1'9 past pinvalve 3I through passage 32.7 Air isvented from space 29 through" passage'. 33 :leak-port 34'. The leak. port is control-led by and or valve'- 35',

531. AMain valve Siririg' 5 holds fria-in and when Wide .open has a `venti-ng capacity in excess of the feeding how past restrictor 3|.

The lid is operated byany suitable device, for example a thermostat, hygrostat or like device responsive to atmospheric conditions; Such device is not illustrated.

A passage Ii; and branch line `2l) I 2 with the device to be controlled'.l

An exhaust valve -housing withexhaust seat 31 is clamped to thecenter of i diaplfiragmy V2I `by nut 33 and two reinforcing discs- 39, 4I... The exhaust valve 42 is a ball urged towardl seat i3-1 `by spririfj 43 which seats on a cup 44 pressed `t0 place. `A thrust plate v45 is xed Jon housing `36` `and engages front diaphragm `25 over nearly the `entire `area of the diaphragni.` PortsMleada from the interior of housing 3E to the space between the diaphragms 2| and-25.

The diaphragm-assembly Vis biased outward by `spring 41.-

OPERATroN (se-Figs. 1- anda) Spring- 4T normally forces diaphragm 2f., erin haus't valve seat 3f?, and diaphragin, ltcvvai cover 24, as Shown in Figure 1. Exhaust valve spring beirig stronger than iiaiti valve spring I6, forcs exhaust valve ball 42- against lits seat valve -bal'l I4 away from seat i8. Main air pressure yis supplied through connection `'f3 to chamber I`-, from whence it passes through main vali/e4 -to chambei` i2 and branch connection 25. Thus, in nits normal position, the two-position.riay'fhasr full pressure in itsbranch line.

Main air from connection 8y also passes thrugwh pin valve 3| to pilot ai-r chamber 29, and escapes to atmosphere through leakporrl 34. Pin valve 3l is so adjusted that, with leakport 34 wide open, the pressure just back ci the leakport is between 4 and 5 inches Water gauge. The opening of leakport 34 may be variedv by movement of lid 35. As lid 35 moves closer to the leakport, less air escapes to atmosphere, and pressure builds up in chamber 29. When the force of this pilot pressure in chamber 2S, acting on diaphragm 25, becomes greater than the force of spring-41 plus the force of the full branch pressure acting on diaphragm ZI, both diapi'ira'grns and exhaust valve seat 31 move in` a direction .avv-ay 'from cover" plate T24. This movement transmitted to'main'valve ball I4 by thrust 'member t5, `themain valve ball seats'at I8. Whei'u'fmain valve' b'alllf I4 isse'ated, no further movement ci this ball takes placgfbiit continued movement of exhaust Vvalve' `seaty T31 `forces exhaust valve'bafll I2 irornf itsseatT-- from chamber I2 and the branch 1in@ l thus escapes to atmosphere through the exhaust valve, and passages 46 and 28. The escape of air :from chamber I2 reduces the pressure acting on diaphragm 2I, thus causing the exhaust valve to open further, assuring that once the :branch pressure starts to escape, the process will continue until all of the air in the branch line is exhausted to atmosphere.

In order again to supply pressure to the branch line, it is necessary to reduce the pilot pressure in chamber 29 by moving lid 35 away from leakport 34. When the force of this pressure on diaphragm 25 becomes less than the force of spring 4'I, both diaphragm and exhaust valve seat 31 are moved toward cover plate 24 by spring II'I. Exhaust valve ball 42 first closes on seat 3l, then For example, spring I6 of Figs. l and 2 is a weak spring used to keep the ball valve I4 from spinning during iiow past it. The valve can be made to function without the spring, but is noisy.

What I claim is:

1. A positive reverse-acting relay comprising in combination, a body having a vsupply chamber adapted for connection with a source of uid under pressure, and a generally circular diaphragm chamber adapted for connection with a device in which pressure is to be controlled; an inlet poppet. valve and seat controlling flow from said supply chamber to said diaphragm chamber, thevalve and its seat being axially alined with the center of the diaphragm chamber and 'Y being arranged to close by motion of the valve main valve ball I4 moves away from seat I8. i

Vthe eiect of this change on diaphragm 2| is such vthat the cycle continues until it is completed. Hence it is impossible for the branch pressure to have any value except Zero or maximum.

DiUerentiaZ.-The differential of'a two-position relay is dened as the difference in pilot pres- `sure between the point at which the relay operates to pass full pressure to the branch line,

andthe point at which it operates to exhaust the branch line, or vice versa. When full pressure exists in the branch line, this pressure operates on diaphragm 2| and helps maintain valve ball I4 open. When no pressure exists in the branch z.,

line there is no force on diaphragm 2I, and the exhaust valve is held open by the force of the pilot pressure on diaphragm 25. Assuming'that the force of spring 41 is constant, the change in pilot pressure multiplied by the area of diaphragm 25, must equal the change in branch pressure multiplied by the area of diaphragm 2 I in order to operate the relay. The areas of the two diaphragms are so selected that, when the maximum branch pressure is p. s. i., the differential is 4 p. s. i. Since the relay is always part of a complete control instrument, such as a thermostat, humidostat, etc., the diierential of the instrument in terms of the controlled variable is determined by the amountoi change in the controlled variable required to produce a given movement of lid 35.

The table shows the diierential of the relay (Fig. l) for various maximum values of branch pressure.

. Table Maximum Pressure Dlfferelltlal P. s, i. P. s. i,

GENERAL CONSIDERATIONS toward the supply chamber whereby the valve is biased in an opening direction by supply pressure; a rear diaphragm closing that side of the Il il diaphragm chamber which is opposite to said inlet valve; an exhaust poppet valve and seat mounted at the center of said diaphragm and laxially alined with said inlet valve, said exhaust phragm, said valve being arranged to close against its seat by motion toward the diaphragm chamber; yielding means biasing said exhaust valve in said closing direction; a front diaphragm arranged to act in thrust on the rear diaphragm; marginal supporting means for sustaining said diaphragms in spaced relation whereby an exhaust path is afforded from the space between the diaphragms; Vmeans enclosing a regulatingpressure chamber at the front of the front diaphragm; means for developing a regulatory pressure in the last-named chamber; yielding means biasing said diaphragms in opposition to said regulatory pressure; and means affording one-way thrust between said supply and exhaust valves, thestrength of the exhaust valvev springbeing such, that under rising regulatory pressure motion of the rear diaphragm first closes the inlet valve and then opens the exhaust valve, and under falling regulatory pressure motion of the rear diaphragm rst closes the exhaust and then opens the inlet valve. Y

l 2. A positive reverse-acting relay comprising vin combination, a body having a supply chamber adapted for connection with a source of uid under pressure, a diaphragm chamber adapted vfor connection with a device in which pressure is to be controlled, and a mount for supporting coaxially with saidl diaphragm chamber an inlet valve assembly adapted to control communication between said chambers; an inlet valve' arssembly supported in said mount and comprising a housing with valve seat, a poppet valve and a spring biasing said valve in its opening direction,

the valve being arranged to close by motionto-l ward the supply chamber; a rear diaphragm closing the side of the said diaphragm chamber opposite to said mount and adapted to support at its center in axial alinement with said inlet valve assembly an exhaust valve assembly adapted to control ow from the diaphragm chamber through said diaphragm; an exhaust valve assembly so supported in said rear diaphragm and 5 said diaphragms; means enclosing a regulatingpressure chamber at the front of the front dia-` phragm; means for developing a regulatory pressure in the last-named chamber; yielding means biasing said diaphragme in opposition to said regulatory pressure; and one-Way thrust means interposed between said valves and guided in one of said valve housings, the relative strengths of the valve springs being such that under rising regulating pressure motion of the diaphragms rst closes the inlet Valve and then opens the exhaust valve and under falling regulating pressure motion of the diaphragms lrst closes the exhaust and then opens the inlet valve.

` ADOLPH J. HILGERT.

6 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

